Wafer alignment markers, systems, and related methods

ABSTRACT

A method of aligning a wafer for semiconductor fabrication processes may include applying a magnetic field to a wafer, detecting one or more residual magnetic fields from one or more alignment markers within the wafer, responsive to the detected one or more residual magnetic fields, determining locations of the one or more alignment markers. The marker locations may be determined relative to an ideal grid, followed by determining a geometrical transformation model for aligning the wafer, and aligning the wafer responsive to the geometrical transformation model. Related methods and systems are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.16/122,062, filed Sep. 5, 2018, now U.S. Pat. No. 11,009,798, issued May18, 2021, which is related to U.S. patent application Ser. No.16/122,106, filed Sep. 5, 2018, now U.S. Pat. No. 11,251,096, issuedFeb. 15, 2022, titled “WAFER REGISTRATION AND OVERLAY MEASUREMENTSYSTEMS AND RELATED METHODS,” the entire disclosure of each of which ishereby incorporated herein by this reference.

TECHNICAL FIELD

This disclosure relates generally to alignment markers, and to methodsof and systems for aligning wafers using alignment markers and, morespecifically, to employing alignment markers exhibiting ferromagnetic orantiferromagnetic characteristics, as well as alignment markersexhibiting active responses to external magnetic stimuli.

BACKGROUND

Photolithography is a process commonly used in semiconductor fabricationfor selectively removing portions of a material from discrete areas of asurface of a semiconductor wafer. A typical photolithography processincludes spin coating a layer of a radiation-sensitive material(commonly referred to as a “photoresist”) onto the surface of thesemiconductor wafer. The semiconductor wafer is then exposed to apattern of radiation that chemically modifies a portion of thephotoresist incident to the radiation. The process further includesremoving either the exposed portion, in the case of a positivephotoresist, or the unexposed portion, in the case of a negativephotoresist, from the surface of the semiconductor wafer with a chemicalsolution (e.g., a “developer”) to form a pattern of openingscorresponding to the pattern of radiation. Subsequently, portions of thematerial on the surface of the semiconductor wafer exposed through theopenings can be selectively removed. Alternatively, portions of amaterial can be deposited onto the surface of the wafer, through theopenings of the photoresist mask. The photolithography process can berepeated to form levels of microelectronic features on or in the wafer.

A significant issue in semiconductor processing is precise alignment ofa semiconductor wafer with respect to a processing tool, and inparticular, photolithography tools. Modern integrated circuits havemultiple levels comprising a variety of materials (e.g., 30 or more)that need to be aligned precisely as the multiple levels are formed onthe wafer. Conventionally, alignment markers are formed before a currentphotolithography step, and may occur at any previous step, and notnecessarily at a beginning of a fabrication process. The alignmentmarkers provide an optically readable indicator of reference points orreference structures on an active surface of a wafer, and are used todetermine the relative orientation of the wafer with respect to aprocessing tool for precise alignment of levels of material ofintegrated circuitry being fabricated. However, typical fabrication andpackaging processes, such as oxide growth, planarization, or metaldeposition, often change critical features of the markers. For example,deposition processes, oxide growth, and removal processes can changemarkers that start out as trenches to mesas, or the processes can alterthe color, contrast, or other properties of the markers used foralignment purposes. Such changes in the alignment markers may causeartifact in optically readings of the marker, resulting in misalignmentamong superimposed levels, which in turn can cause short-circuiting,misaligned contacts, misaligned vias, disconnections, and otherstructural deficiencies leading to failure of semiconductor dicesingulated from the wafer.

One optical alignment method is manual alignment. Operators using amicroscope view the position of a wafer and make adjustments as neededby using a computer that controls an actuator to move a wafer supportcarrying the wafer. This method is slow, inaccurate, and has a highyield loss due to misalignment even among the most conscientiousoperators. Other methods such as wafer probing and mechanically scanningpoint sensors have automated the manual process. However, these methodscontinue to produce wafers with high yield loss or devices thatmalfunction due to misalignment and are limited by optical visibility ofmarkers.

BRIEF DESCRIPTION OF THE DRAWINGS

For a detailed understanding of the present disclosure, reference shouldbe made to the following detailed description, taken in conjunction withthe accompanying drawings, in which like elements have generally beendesignated with like numerals, and wherein:

FIG. 1 is a schematic representation of an alignment system according toone or more embodiments of the present disclosure;

FIG. 2A is a simplified top view of an alignment system superimposedover a wafer having alignment markers formed therein according to one ormore embodiments of the present disclosure;

FIG. 2B is a partial side cross-sectional view of a wafer havingalignment markers formed therein according to one or more embodimentspresent disclosure;

FIG. 3 is a flow diagram of a method of aligning a wafer according toone or more embodiments of the present disclosure;

FIG. 4 is a schematic representation of a sensor oriented over analignment marker within a wafer and a scalar magnitude of a measuredmagnetic field emitted by the alignment marker according to one or moreembodiments of the present disclosure;

FIG. 5 is a schematic representation of a sensor over an alignmentmarker within a wafer according to one or more embodiments of thepresent disclosure;

FIG. 6 shows example measurements acquired via testing performed by theinventors;

FIG. 7 shows example measurements acquired via testing performed by theinventors;

FIG. 8 shows example measurements acquired via testing performed by theinventors;

FIG. 9 shows example measurements acquired via testing performed by theinventors;

FIG. 10 is a flow diagram of a method of aligning a wafer according toone or more embodiments of the present disclosure;

FIG. 11 is a schematic representation of a sensor oriented over analignment marker within a wafer and a scalar magnitude of a measuredmagnetic field emitted by the alignment marker according to one or moreembodiments of the present disclosure;

FIG. 12 is a schematic representation of a sensor over an alignmentmarker within a wafer and a scalar magnitude of a measured magneticfield emitted by the alignment marker according to one or moreembodiments of the present disclosure;

FIG. 13 is a flow diagram of a method of aligning a wafer according toone or more embodiments of the present disclosure; and

FIG. 14 is a schematic view of a sensor head of a registration systemaccording to one or more embodiments of the present disclosure.

DETAILED DESCRIPTION

The illustrations presented herein are not actual views of any alignmentsystem or any component thereof, but are merely idealizedrepresentations, which are employed to describe embodiments of thepresent invention.

As used herein, the singular forms following “a,” “an,” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise.

As used herein, the term “may” with respect to a material, structure,feature, or method act indicates that such is contemplated for use inimplementation of an embodiment of the disclosure, and such term is usedin preference to the more restrictive term “is” so as to avoid anyimplication that other compatible materials, structures, features, andmethods usable in combination therewith should or must be excluded.

As used herein, any relational term, such as “first,” “second,” “above,”“upper,” etc., is used for clarity and convenience in understanding thedisclosure and accompanying drawings, and does not connote or depend onany specific preference or order, except where the context clearlyindicates otherwise. For example, these terms may refer to orientationsof elements of an alignment system and/or wafer in conventionalorientations. Furthermore, these terms may refer to orientations ofelements of an alignment system and/or wafer as illustrated in thedrawings.

As used herein, the term “substantially” in reference to a givenparameter, property, or condition means and includes to a degree thatone skilled in the art would understand that the given parameter,property, or condition is met with a small degree of variance, such aswithin acceptable manufacturing tolerances. By way of example, dependingon the particular parameter, property, or condition that issubstantially met, the parameter, property, or condition may be at least90.0% met, at least 95.0% met, at least 99.0% met, or even at least99.9% met.

As used herein, the term “about” used in reference to a given parameteris inclusive of the stated value and has the meaning dictated by thecontext (e.g., it includes the degree of error associated withmeasurement of the given parameter, as well as variations resulting frommanufacturing tolerances, etc.).

As used herein, the term “wafer” means and includes materials upon whichand in which structures including feature dimensions of micrometer andnanometer scale are partially or completely fabricated. Such materialsinclude conventional semiconductor (e.g., silicon) wafers, as well asbulk substrates of other semiconductor materials as well as othermaterials. For the sake of convenience, such materials will bereferenced below as “wafers.” Example structures formed on suchmaterials may include, for example, integrated circuitry (active andpassive), MEMS devices, and combinations thereof.

Many details of certain embodiments are described below with referenceto semiconductor devices. The term “semiconductor device” is usedthroughout to include a variety of articles of manufacture, including,for example, individual integrated circuit dies, imager dies, sensordies, and/or dies having other semiconductor features. The semiconductordevice or semiconductor device portions (e.g., semiconductor deviceforms) may be unsingulated silicon comprising die locations, or acarrier semiconductor device repopulated with previously singulateddice. The repopulated carrier semiconductor device can include anadhesive molding material (e.g., a flexible adhesive), which issurrounded by a generally rigid frame having a perimeter shapecomparable to that of device wafer, and laterally separated singulatedelements (e.g., dies) surrounded by the molding material.

Some embodiments of the present disclosure include alignment systems andmethods for aligning a wafer at least partially based on detectingand/or measuring magnetic attributes of alignment markers within thewafer. For example, some embodiments include alignment systems andmethods for forming alignment markers within wafer with ferromagnetic orantiferromagnetic materials or any other material or structure capableof interacting with a magnetic field, and applying a magnetic field tothe wafer to magnetize the alignment marker. Moreover, the alignmentsystems may detect one or more residual magnetic fields from,magnetizations of, or signals from one or more alignment markers withinthe wafer, and responsive to the detected one or more residual magneticfields, magnetization, and/or signals, the alignment systems maydetermine actual locations of the alignment markers relative to an idealgrid of such markers. Furthermore, responsive to the determinedlocations, the alignment systems may determine a geometricaltransformation model to compensate for deviations in alignment markerplacement from the ideal for aligning the wafer and may align the waferresponsive to the geometrical transformation model.

FIG. 1 is a schematic view of an alignment system 100 according to oneor more embodiments of the present disclosure. The alignment system 100can be used to align a wafer and for the performance of processes forsemiconductor fabrication, for example, photolithographic processesinvolving selective exposure of a material on the wafer to light througha patterned reticle. It will be appreciated that the present technologyis not limited to use in conjunction with photolithography tools but isalso applicable to other semiconductor processing tools that requireaccurate alignment of a wafer relative to the processing tool or otherelements (e.g., registration systems and overlay measurements). As anon-limiting example, the present technology can be used in conjunctionwith laser cutting and drilling tools, saws, 3-D printing tools, andother processes that necessitate precise alignment of wafers. Forpurposes of illustration, the alignment system 100 includes a sensor102, a magnetic source 104, and a substrate support 106.

As shown in FIG. 1 , a controller 118 may be operatively coupled to thesensor 102, the magnetic source 104, and the substrate support 106 ofthe alignment system 100 for monitoring or controlling the operation ofthese components. Although not shown in FIG. 1 , the alignment system100 may also have associated therewith a substrate transport station, astructural support (e.g., a reticle support, a lens support, etc.),position sensors (e.g., a scatterometer), an immersion hood, a supportactuator (e.g., an electric motor), and/or other suitable mechanicaland/or electrical components. In general, the controller 118 may move awafer and/or components of the alignment system 100 before, during,and/or after a semiconductor fabrication process. For example, a wafer114 can undergo photoresist application, patterning, developing, baking,cleaning, deposition or formation of additional material levels, and/orother suitable processing, and the alignment system 100 may be used toalign the wafer 114 and/or tool components associated with the alignmentsystem 100 before, during, and/or after these processes.

The controller 118 may include a processor 120 coupled to a memory 122and an input/output component 124. The processor 120 may include amicroprocessor, a field-programmable gate array, and/or other suitablelogic devices. The memory 122 may include volatile and/or nonvolatilemedia (e.g., ROM, RAM, magnetic disk storage media, optical storagemedia, flash memory devices, and/or other suitable storage media) and/orother types of computer-readable storage media configured to store data.The memory 122 may store algorithms for alignment, edge detection,processing data related to detected magnetic fields and detectedmagnetizations, emitting magnetic fields, filters, and shape recognitionto be executed by the processor 120. In some embodiments, the processor120 is operably coupled to send data to a computing device operativelycoupled (e.g., over the Internet) to the controller 118, such as aserver or personal computer. The input/output component 124 can includea display, a touch screen, a keyboard, a mouse, and/or other suitabletypes of input/output devices configured to accept input from andprovide output to an operator.

In the embodiment illustrated in FIG. 1 , the alignment system 100 mayutilize the sensor 102 to determine (e.g., read) locations of alignmentmarkers disposed within a wafer and send captured location data to thecontroller 118, where it is stored in the memory 122, processed by theprocessor 120, and/or sent to the input/output component 124. As isdiscussed in greater detail below, the alignment system 100 may utilizethe sensor 102 to detect one or more magnetic attributes of alignmentmarkers within the wafer 114. In some embodiments, the alignment system100 may utilize the sensor 102 to detect the locations of magneticfields emitted by the alignment markers disposed within the wafer, andresponsive to the detected magnetic field locations, the alignmentsystem 100 may determine the locations of the alignment markers disposedin the wafer, as is described in greater detail below in regard to FIGS.3-9 . In additional embodiments, the photolithography system 100 mayutilize the sensor 102 to measure magnetization field strength of therespective alignment markers disposed within the wafer, and responsiveto the measured field strengths of the respective alignment markers, thealignment system 100 may determine the locations of the alignmentmarkers disposed in the wafer, as is described in greater detail belowin regard to FIGS. 10-12 . In yet further embodiments, the alignmentsystem 100 may utilize the sensor 102 to detect responses from alignmentmarkers (in this case, circuits) powered inductively by the magneticsource 104, and based at least in part on the responses, the alignmentsystem 100 may determine the locations of the alignment markers disposedin the wafer, as is described in greater detail below in regard to FIG.13 . Furthermore, the alignment system 100 may utilize the determinedlocations of the alignment markers to align the wafer 114 for furthersemiconductor fabrication processing (e.g., exposure procedures). Forinstance, the alignment system 100 may utilize the determined locationsof the alignment markers to align the wafers in conjunction withconventional methods for aligning wafer with alignment markers.

In some embodiments, the sensor 102 may include a magnetic sensor. Inone or more embodiments, the sensor 102 may include a Hall Effectsensor. For instance, the sensor 102 may include a transducer thatvaries the transducer's output voltage in response to a detectedmagnetic field. In additional embodiments, the sensor 102 may includeone or more of a giant magnetoresistance (GMR) sensor, a tunnelmagnetoresistance (TMR) sensor, an electromagnetic radiation (EMR)sensor, or a spin hall sensor. In further embodiments, the sensor 102may include a magnetic force microscopy (MFM) probe (e.g., a magneticforce microscope). For instance, the sensor 102 may include a sharpmagnetized tip for scanning the alignment markers, where interactionsbetween the tip and the alignment markers (e.g., deflections of the tip)are detected and utilized to reconstruct magnetic structures of thealignment markers. In some embodiments, the sensor 102 may include oneor more of a superconducting quantum interference device (SQUID) or avibrating sample magnetometer (VSM). The operation of the sensor 102 isdescribed in greater detail below in regard to FIGS. 4, 5, 11, and 12 .

The alignment system 100 may utilize the magnetic source 104 to apply amagnetic field to the wafer 114 (e.g., emit a magnetic field through thematerial of wafer 114) and any alignment markers included within thewafer 114, to magnetize the alignment markers within the wafer 114,and/or to power the alignment markers within the wafer 114. In someembodiments, the magnetic source 104 may include a permanent magnet. Inadditional embodiments, the magnetic source 104 may include anelectromagnet. For instance, the magnetic source 104 may include anyelectromagnet known in the art. Furthermore, in some embodiments, themagnetic source 104 may be sized and shaped for applying a magneticfield to an entirety of the wafer 114 (e.g., all the alignment markerswithin the wafer 114). In other embodiments, the magnetic source 104 maybe sized and shaped for applying a magnetic field to only selectedportions of the wafer 114 (e.g., a group of alignment markers, a regionof the wafer 114, etc.). In one or more embodiments, the magnetic source104 may be disposed within a probe carrying the sensor 102. Forinstance, the magnetic source 104 may include an inductor disposedproximate to the sensor 102, to be used to magnetize alignment markersin their respective locations without subjecting the entire wafer tomagnetic fields and prior to use of sensor 102 on the probe. In otherembodiments, magnetic source 104 may be omitted, and wafer 114 subjectedto a magnetic source after alignment markers 202 are formed and beforeplacement of wafer 114 on the substrate support of photolithographysystem 100. In further embodiments, the magnetic source 104 may becarried on a probe moveable under wafer 114 in alignment with a probecarrying sensor 102 to stimulate a response from each marker alignedbetween the sensor 102 and the magnetic source 104.

The substrate support 106 may be configured to carry and/or move thewafer 114. The substrate support 106, which may also be characterized asa platform or a stage, may include a vacuum chuck, a mechanical chuck,and/or other suitable supporting devices. Although not shown in FIG. 1 ,the alignment system 100 may include at least one actuator configured tomove the substrate support 106 laterally (as indicated by the X-axis),transversely (as indicated by the Y-axis), and/or vertically (asindicated by the Z-axis) relative to the sensor 102 and/or othercomponents of the alignment system 100. As used herein, the X-axis,Y-axis, and Z-axis as depicted in FIG. 1 define a Cartesian space. Incertain embodiments, the substrate support 106 can also include positionmonitors (not shown) such as linear encoders, configured to monitor theposition of the substrate support 106 along the X-axis, the Y-axis,and/or the Z-axis. In addition, a rotary encoder may be employed tomonitor a rotational position of the wafer about the Z-axis. Even thoughonly one substrate support 106 is shown in FIG. 1 , in certainembodiments, the alignment system 100 can include two, three, or anydesired number of substrate supports with structures and/or functionsthat are generally similar to or different than the substrate support106, so that multiple wafers may be moved into and out of alignment withthe remainder of alignment system 100 in an expedited fashion. Inoperation, the controller 118 may be used to position the substratesupport 106 to properly align the wafer 114 with tools or othercomponents associated with the alignment system 100 according to aspectsof the present technology described below.

In some embodiments, the alignment system 100 may additionally includecomponents of conventional alignment systems known in the art. Forinstance, the alignment system 100 may additionally include an opticalalignment system (e.g., an optical microscope imaging or scatterometrysystem) that may be used in conjunction with the alignment system 100 ofthe present disclosure. As a non-limiting example, the alignment system100 may include an image sensor, an illumination source, a condenserlens, a reticle, and/or an objective lens and may be capable ofperforming any of the alignment procedures (e.g., alignment models)associated with the foregoing components. For example, thephotolithography system 100 may additionally include the alignmentsystem described in U.S. Pat. No. 9,748,128, to Chao et al., issued Aug.29, 2017.

FIG. 2A is a schematic top view of a wafer 114 and sensor 102 (e.g.,probe) of an alignment system (e.g., alignment system 100) according toone or more embodiments of the present disclosure. FIG. 2B is aschematic partial side cross-sectional view of the wafer 114 of FIG. 2Aaccording to one or more embodiments of the present disclosure.Referring to FIGS. 2A and 2B together, in some embodiments, the wafer114 may include alignment markers 202 disposed within the wafer 114.

In some embodiments, the alignment markers 202 may be disposed withinwafer 114 within a predetermined pattern 204. For instance, thealignment markers 202 may be oriented relative to one another in thepattern 204 to assist in aligning the wafer 114 prior to one or moresemiconductor fabrication. Furthermore, as is discussed in greaterdetail below, the pattern 204 may be formed via conventional methodsknown in the art. As is depicted in FIG. 2B, in some embodiments, thealignment markers 202 may be disposed in a lower level of processing(e.g., a level created in a previous procedure) of the wafer 114, andnow hidden from sight. For instance, as shown in FIG. 2B, the alignmentmarkers 202 may be disposed beneath one or more additional levels 206(e.g., overlying levels) on an active surface of the wafer 114. In someembodiments, the alignment markers 202 may be disposed beneath one ormore opaque and/or relatively thick material levels. For clarity, theone or more additional material levels 206 are removed in FIG. 2A. Insome embodiments, the alignment markers may be disposed in an activesurface of a pristine semiconductor wafer, prior to any processing forforming integrated circuitry thereon.

In one or more embodiments, the alignment markers 202 may each have acircular cross-section along a plane parallel to an upper surface of thewafer 114. In additional embodiments, the alignment markers 202 may haveany other shaped cross-section. For example, the alignment markers 202may have a general cuboid shape (e.g., flat rectangle shape).Additionally, the alignment markers 202 may have any polygonal shape. Ofcourse, alignment markers on an active surface of a wafer may all havethe same shapes, or different shapes.

The one or more alignment markers 202 may include ferromagnetic and/orantiferromagnetic materials or any other material capable of interactingwith magnetic fields. As is known in the art, ferromagnetic materialscontain unpaired electrons, each with a small magnetic field of its own,that align readily with each other in response to an applied externalmagnetic field. The alignment of the electrons tends to persist evenafter the external magnetic field is removed, due to a phenomenon calledmagnetic hysteresis. In some embodiments, the one or more alignmentmarkers 202 may include one or more of iron, alnico alloys (e.g., ironalloys including aluminum, nickel, and/or cobalt), bismanol (i.e.,bismuth and manganese alloy), chromium (IV) oxide, cobalt, fernicoalloys, ferrite, gadolinium, gallium manganese arsenide, magnadur (i.e.,sintered barium ferrite), magnetite, nickel, etc. In antiferromagneticmaterials, magnetic moments of atoms or molecules, usually related tospins of electrons, align in a regular pattern with neighboring spinspointing in opposite directions. Antiferromagnetic materials maycomprise transition metal compounds, such as oxides. Examples includehematite, chromium, iron manganese, and nickel oxide.

First Set of Embodiments

FIG. 3 shows a schematic flow diagram of a method 300 of aligning awafer for performance of semiconductor fabrication processes accordingto a first set of embodiments of the present disclosure. As is describedin greater detail below, the first set of embodiments may includeprocedures that involve determining locations of alignment markers 202and an overall orientation of a wafer 114 responsive to magnetic fieldsemitted by the alignment markers 202, and aligning the wafer 114responsive to the determined locations.

As is shown in FIG. 3 , the method 300 may include creating a pattern204 in a surface (e.g., upper surface) of a wafer 114 by removingmaterial from the semiconductor material of wafer 114, as shown in act302. In some embodiments, the pattern 204 may be created viaconventional lithographic processes and methods. For instance, photoresist application, patterning and etching (chemical or reactive ionetching), or focused ion beam processes (e.g., ion milling), etc., maybe employed to form a pattern of recesses in the semiconductor materialof wafer 114 prior to further processing of wafer 114 for fabrication ofintegrated circuitry thereon. Furthermore, in some embodiments, thecreated pattern 204 may correlate to (e.g., have the same size and shapeas a pattern of) an ideal grid (e.g., ideal pattern and ideal positionof the alignment markers 202 for orientation of the wafer 114). As isknown in the art, positions and locations of alignment markers within awafer are conventionally compared to an ideal grid to determinealignment procedures and movements (e.g., alignment models).

In some embodiments, the pattern 204 may be formed such that resultingalignment markers 202 (described below in regard to acts 304 and 306)formed within the pattern 204 have a particular orientation and/orgeometry. For instance, the pattern 204 may be formed such thatresulting alignment markers 202, when magnetized, have poles (e.g.,magnetic poles) disposed along a particular axis (e.g., X-axis, Y-axis,or Z-axis) of the Cartesian space defined above in regard to FIG. 1 .Additionally, recesses of the pattern 204 may be formed for creation ofalignment markers 202 of particular geometric shapes. As a result, theorientations, geometries, and locations of the alignment markers 202 maybe predetermined.

In some embodiments, the pattern 204 may be formed such thatlongitudinal lengths of the resulting alignment markers 202 are at leastsubstantially parallel to one of the X-axis, Y-axis, or Z-axis of theCartesian space. Furthermore, the alignment system 100 may form thepattern 204 such that each of the resulting alignment markers 202 has acommon directional orientation.

The method 300 may also include filling recesses of the pattern 204 withferromagnetic and/or anti ferromagnetic materials or any other materialor structure capable of interacting with a magnetic field to form thealignment markers 202, as shown in act 304 of FIG. 3 . For instance, act304 may include filling recesses of the pattern 204 with any of thematerials described above in regard to FIGS. 2A and 2B. Furthermore,recesses of the pattern 204 may be filled via conventional methods. Forexample, recesses of the pattern 204 may be filled with the desiredmaterial via electroplating, electroless plating, physical vapordeposition, chemical vapor deposition, ion beam deposition, thin filmdeposition, etc. The surface of wafer 114 may then be subjected to amaterial removal process such as, for example, chemical mechanicalplanarization (CMP) to remove material from the wafer surface. Inalternative embodiments, the method 300 may not include forming one ormore recesses in the wafer 114 and then filling the one or more recesseswith magnetic material. Rather, the method 300 may include depositingmagnetic material on the wafer and patterning the magnetic materialdirectly. In some embodiments, the recesses of the pattern 204 may befilled to enable for greater dry etches and critical path method ofcritical dimension uniformity while not effecting the alignment markers'202 performance.

In some embodiments, the alignment markers 202 formed via filling thepattern 204 may include nanostructures. For example, the alignmentmarkers 202 may have at least one dimension on the nanoscale. Inadditional embodiments, the alignment markers 202 formed via filling thepattern 204 may include microstructures. For instance, the alignmentmarkers 202 may have at least one dimension on the microscale. As anon-limiting example, in one or more embodiments, an alignment marker202 may include a 500 nm×100 μm×20 μm rectangular prism alignmentmarker. In additional embodiments, an alignment marker 202 may include a4 μm×100 μm×20 μm rectangular prism alignment marker. In furtherembodiments, an alignment marker 202 may include a 500 nm×50 μm×5 μmrectangular prism alignment marker. In yet further embodiments, analignment marker 202 may include a 1.5 μm×1.5 μm×250 μm pillar alignmentmarker. Although specific dimensions are described herein, the alignmentmarkers 202 may additionally have any conventional dimension ofalignment markers.

After filling the pattern 204 with ferromagnetic and/or antiferromagnetic materials, deviations of the pattern 204 from an idealgrid may be determined, wafer 114 aligned for processing, and additionalsemiconductor fabrication processes (e.g., depositing layers, etching,etc.) may be initiated. For example, one or more material levels (e.g.,overlying levels) may be formed over the alignment markers 202 of thewafer 114. As a result of subsequent semiconductor fabrication processesand/or movements of the wafer 114 during such processes, knownorientations of the wafer 114 and/or orientations and locations of thealignment markers 202 may become inaccurate. As a result, any previouslyknown positions of features on wafer 114 may become inaccurate, and theposition of wafer 114 may be recalibrated prior to further processing tosecure precise alignment of features created in various additional,superimposed levels.

When initiating an alignment procedure, the method 300 may includeapplying an external magnetic field to the wafer 114, as shown in act306. For instance, the alignment system 100 may apply an externalmagnetic field to the wafer 114 (e.g., subject the wafer 114 to amagnetic field) via the magnetic source 104 described above in regard toFIG. 1 . For example, the alignment system 100 may supply a currentthrough a coil of wire wrapped around an iron core to create an externalmagnetic field. In some embodiments, the alignment system 100 may supplya sufficient amount of current to create an external magnetic fieldhaving a strength greater than 25 Oersteds (Oe). In one or moreembodiments, the alignment system 100 may apply the external magneticfield to the wafer 114 immediately following filling the pattern 204with ferromagnetic and/or anti ferromagnetic materials (i.e., act 304 ofFIG. 3 ). In additional embodiments, the alignment system 100 may applythe external magnetic field to the wafer 114 after one or moresubsequent semiconductor fabrication processes and prior to or whilealigning the wafer 114 before initiating an additional semiconductorfabrication process. In some embodiments, applying the external magneticfield to the wafer 114 is optional. For instance, the alignment markers202 may already be magnetized or may be interacting within magneticfields.

In some embodiments, the alignment system 100 may apply an initialexternal magnetic field (Hex) to the wafer 114 to orient vectors of theresulting magnetic fields of the alignment markers 202. For instance,the alignment system 100 may apply an initial external magnetic field(Hex) to the wafer 114 to rotate all domains within the alignmentmarkers 202 to be in known directions. As a result, and as is discussedin further detail below, orienting all the domains of the alignmentmarkers 202 enables the alignment system 100 to determine (e.g., know,set, etc.) desired orientation of magnetic fields for each alignmentmarker 202 (e.g., a magnetic field that is expected to be emitted byeach alignment marker 202 in response to being magnetized). Furthermore,applying the initial external magnetic field (Hex) to the wafer 114forces the resulting magnetic fields of the alignment markers 202 to beoriented in a particular (e.g., selected) direction.

After applying the initial external magnetic field to the wafer 114, thealignment system 100 may apply an additional external magnetic field tothe wafer 114 to at least partially magnetize the alignment markers 202within the wafer 114. In some embodiments, the alignment system 100 mayapply the additional external magnetic field to the wafer 114 in aparticular direction. For example, the alignment system 100 may applythe additional external magnetic field to the wafer 114 in plane withthe wafer 114. In other words, the alignment system 100 may apply theadditional external magnetic field to the wafer 114 along a plane thatis parallel to an upper surface of the wafer 114. In additionalembodiments, the alignment system 100 may apply the additional externalmagnetic field to the wafer 114 out of plane with the wafer 114. Putanother way, the alignment system 100 may apply the additional externalmagnetic field to the wafer 114 along a plane that is perpendicular toor forming an acute angle with the upper surface of the wafer 114.

In some embodiments, a direction in which the external magnetic field isemitted through the wafer 114 may be dependent on orientation of thealignment markers 202 within the wafer 114. For example, in one or moreembodiments, the alignment system 100 may emit the external magneticfield in a direction that is parallel to or perpendicular to a directionextending from a first pole (e.g., north-seeking pole) of a givenalignment marker 202 to a second pole (e.g., south-seeking pole) of thegiven alignment marker 202. As mentioned briefly above, the direction inwhich the external magnetic field is applied to the alignment markers202 may determine expected responses of the alignment markers 202 (e.g.,expected resulting magnetic fields of the alignment markers 202).

In one or more embodiments, the alignment system 100 may only apply asingle external magnetic field to the wafer 114 to both orient thedomains of the alignment markers 202 and to magnetize the alignmentmarkers 202. In other words, the alignment system 100 may not apply asecond subsequent external magnetic field to the wafer 114 in everyembodiment.

As will be appreciated by one of ordinary skill in the art, applying anexternal magnetic field to a ferromagnetic and/or antiferromagneticmaterials may cause residual (e.g., remanent) magnetic fields to beemitted by the alignment markers 202 even after removing the appliedexternal magnetic field. For instance, the alignment markers 202 maymaintain a remanence (e.g., remanent magnetization or residualmagnetism). Furthermore, because the pattern 204 in which the alignmentmarkers 202 were formed is known, and because the original orientationof the alignment markers 202 is known, the alignment markers 202 haveexpected pole locations, sizes, geometries, and orientations relative toone another and within the wafer 114. Referring to acts 302-306together, in some embodiments, the pattern 204 and alignment markers 202may be formed and the alignment system 100 may then be used to apply theexternal magnetic field to result in the poles of the alignment markers202 being aligned along one of the axes of the Cartesian space definedabove (e.g., the X-axis, Y-axis, or Z-axis). As a result, the alignmentmarkers 202, after being magnetized, may have expected resultingmagnetic fields.

Upon applying an external magnetic field, the method 300 may includedetermining (e.g., reading) locations of the alignment markers 202within the wafer 114, as shown in act 308 of FIG. 3 . In someembodiments, determining the locations of alignment markers 202 withinthe wafer 114 may include one or more of 1) measuring magnitudes of themagnetic fields (i.e., residual magnetic fields) emitted by thealignment markers 202 in a scalar form along one or more axes, as shownin act 308 a, 2) calculating magnetic field strengths of the magneticfields of the alignment markers 202 in a vector form along one or moreaxes, as shown in act 308 b, and ultimately, 3) determining thelocations of the alignment markers 202 responsive to data determined inacts 308 a and/or 308 b, as shown in act 308 c. Furthermore, in someembodiments, act 306 of FIG. 3 (i.e., the act of applying a magneticfield to the wafer 114) may be repeated during and/or between any of theactions taken in act 308 to maintain and/or recreate magnetic fieldswithin the alignment markers 202. If desired, act 308 may be repeated toverify the previously obtained data relating to alignment markers 202.

FIG. 4 is a schematic representation 400 of an alignment marker 202within a wafer 114 and a sensor 102 of an alignment system (e.g.,alignment system 100) disposed over the wafer 114. Additionally, FIG. 4shows example scalar magnitudes of magnetic fields detected via thesensor 102 when passing the sensor 102 over an upper surface 402 of thewafer 114 and above the alignment marker 202 within the wafer 114.Referring to act 308 a of FIG. 3 and FIG. 4 together, the alignmentsystem 100 may pass the sensor 102 over the upper surface 402 of thewafer 114 to detect the magnetic fields emitted by the alignment markers202 within the wafer 114. In some embodiments, the alignment system 100may pass the sensor 102 over the wafer 114 along one or more of theX-axis, Y-axis, and/or Z-axis of the Cartesian space defined above inregard to FIG. 1 . For instance, the alignment system 100 may pass thesensor 102 along the X-axis to detect magnitudes of magnetic fieldsemitted by the alignment markers 202 along the X-axis of the Cartesianspace. As noted above, within the first set of embodiments, the sensor102 may include one or more of a Hall Effect sensor, a GMR sensor, a TMRsensor, an EMR sensor, or a spin hall sensor.

In some embodiments, the alignment system 100 may pass the sensor 102over the upper surface of the wafer 114 along multiple axes (e.g., boththe X-axis and the Y-axis) of the Cartesian space to detect magnitudesand directions of a magnetic field emitted by a given alignment marker202 within the wafer 114 along the multiple axes. In one or moreembodiments, an expected location and orientation of a given alignmentmarker 202 (e.g., a location determined by the pattern 204 previouslyformed and material previously deposited to form the given alignmentmarker 202, as discussed above in regard to acts 302 and 304) stored inmemory 122 may be used by processor 120 to determine where the alignmentsystem 100 passes the sensor 102 over the wafer 114 and along which axesthe alignment system 100 passes the sensor 102 to detect (e.g., searchfor) the magnetic field emitted by the given alignment marker 202.

Additionally, referring to act 308 b of FIG. 3 , as noted above, in someembodiments, determining locations of the alignment markers 202 withinthe wafer 114 may include calculating the magnetic field strengths ofthe magnetic fields emitted by the alignment markers 202 in vector form.In some embodiments, the alignment system 100 may calculate the magneticfield strengths of the magnetic fields emitted by the alignment markers202 in vector form by approximating the magnetic fields as dipolesand/or surface magnetic moments. For example, FIG. 5 is a schematicrepresentation 500 of an alignment marker 202 disposed within a wafer114 and a sensor 102 of an alignment system (e.g., alignment system 100)disposed over the wafer 114.

Referring to FIGS. 3 and 5 together, the alignment system 100 may passthe sensor 102 over the upper surface 402 of the wafer 114 to detect themagnetic fields emitted by the alignment markers 202 within the wafer114 via any of the manners described above in regard to FIG. 4 .Furthermore, as will be understood by one of ordinary skill in the art,when the poles of the alignment markers 202 are closely spaced relativeto an observation distance (d), the magnetic field strengths of themagnetic fields emitted by the alignment markers 202 can be approximatedas dipoles

$\left( {\frac{1}{r^{3}}\mspace{14mu}{dependence}} \right).$Additionally, when the poles of the alignment markers 202 are widelyspaced relative to the observation distance (d), the magnetic fieldstrengths of the magnetic fields emitted by the alignment markers 202can be approximated by the surface magnetic moment

$\left( {\frac{1}{r^{2}}\mspace{14mu}{dependence}} \right).$For instance, the magnetic field strength may be calculated via thefollowing equation:

$H_{dip} = {\frac{1}{\mu_{0}}\frac{{3\left( {m*r} \right)r} - {mr}^{2}}{r^{5}}}$where H_(dip) is the magnetic field strength in vector form, r is thevector from the position of the dipole to the position where themagnetic field is being measured, r is the absolute value of r: thedistance from the dipole, m is the vector dipole moment, and μ₀ is thepermeability of free space.

By utilizing the sensor 102 and passing the sensor 102 over the wafer114 along multiple axes, processor 120 of the alignment system 100 maybe used to calculate the magnetic field strengths of the magnetic fieldsemitted by the alignment markers 202 in vector form (e.g., Hx, Hy, andHz) along one or more of the X-axis, the Y-axis, and the Z-axis of theCartesian space. As a result, the alignment system 100 may calculate arepresentation of the magnetic fields in vectors. In some embodiments,the foregoing equation and approximations may drive the size and shapeof the alignment markers 202 created via acts 302-306 of FIG. 3 , and asa result, the pattern 204 formed in act 302 of FIG. 3 . For instance,the size and shape of the alignment markers 202 (e.g., the pattern 204for forming the alignment markers 202) may be designed to have resultingmagnetic poles of the alignment markers 202 be widely or closely spacedsuch that the resulting magnetic fields can be approximated according toone of the above mentioned methods.

In some embodiments, the alignment system 100 may perform both acts 308a and 308 b when determining a location of an alignment marker 202within the wafer 114. In other embodiments, the alignment system 100 mayperform only one of acts 308 a and 308 b when determining a location ofan alignment marker 202 within the wafer 114. In other words, both ofacts 308 a and 308 b are not required in every embodiment of the presentdisclosure.

The following are simulations of tests performed by the inventors withinthe scope of the first set of embodiments where the magnetic fieldstrengths of magnetic fields emitted by alignment markers arecalculated.

EXAMPLE 1

FIG. 6 shows testing results 600 from laboratory testing from a firstexample. Referring to FIGS. 3-6 together, in the laboratory tests, twotypes of 500 nm×100 μm×20 μm alignment markers (relatively thinspecimen) were disposed within respective wafers. The first type ofalignment marker included Fe65Co35, and the second type of alignmentmarker included Co20Ni80. Four alignment markers of the first type ofalignment markers were disposed at varying depths (250 nm, 1 μm, 3 μm,and 10 μm) within four respective wafers. Additionally, four alignmentmarkers of the second type of alignment markers were disposed at varyingdepths (250 nm, 1 μm, 3 μm, and 10 μm) within four respective wafers.All of the wafers were subjected to a magnetic field greater than 25 Oe.Furthermore, the wafers were subjected to an in plane magnetic field(e.g., magnetic field emitted in a direction parallel to a plane definedby an upper surface of a respective wafer). After subjecting the wafersto the magnetic field, the residual magnetic fields of the alignmentmarkers were detected at the four correlating depths of the alignmentmarkers (250 nm, 1 μm, 3 μm, and 10 μm) and along both the X-axis andthe Z-axis utilizing one or more of the sensors described above.Furthermore, based on the detected magnetic fields, the correlatingmagnetic field strengths were calculated along both the X-axis and theZ-axis (shown in the associated graphs of FIG. 6 ) via one or more ofthe approximation methods described above.

EXAMPLE 2

FIG. 7 shows testing results 700 from laboratory testing from a secondexample. Referring to FIGS. 3-5 and 7 together, in the laboratory tests,two types of 4.0 μm×100 μm×20 μm alignment markers (relatively thickspecimen) were disposed within respective wafers. The first type ofalignment marker included Fe65Co35, and the second type of alignmentmarker included Co20Ni80. Four alignment markers of the first type ofalignment markers were disposed at varying depths (250 nm, 1 μm, 3 μm,and 10 μm) within four respective wafers. Additionally, four alignmentmarkers of the second type of alignment markers were disposed at varyingdepths (250 nm, 1 μm, 3 μm, and 10 μm) within four respective wafers.All of the wafers were subjected to a magnetic field greater than 25 Oe.Furthermore, the wafers were subjected to an in plane magnetic field(e.g., magnetic field emitted in a direction parallel to a plane definedby an upper surface of a respective wafers). After subjecting the wafersto the magnetic field, the residual magnetic fields of the alignmentmarkers were detected at the four correlating depths of the alignmentmarkers (250 nm, 1 μm, 3 μm, and 10 μm) and along both the X-axis andthe Z-axis utilizing one or more of the sensors described above.Furthermore, based on the detected magnetic fields, the correlatingmagnetic field strengths were calculated along both the X-axis and theZ-axis (shown in the associated graphs of FIG. 7 ) via one or more ofthe approximation methods described above.

EXAMPLE 3

FIG. 8 shows testing results 800 from laboratory testing from a thirdexample. Referring to FIGS. 3-5 and 8 together, in the laboratory tests,two types of 500 nm×50 μm×5 μm alignment markers (relatively thinspecimen) were disposed within respective wafers. The first type ofalignment marker included Fe65Co35, and the second type of alignmentmarker included Co20Ni80. Four alignment markers of the first type ofalignment markers were disposed at varying depths (250 nm, 1 μm, 3 μm,and 10 μm) within four respective wafers. Additionally, four alignmentmarkers of the second type of alignment markers were disposed at varyingdepths (250 nm, 1 μm, 3 μm, and 10 μm) within four respective wafers.All of the wafers were subjected to a magnetic field greater than 25 Oe.Furthermore, the wafers were subjected to an in plane magnetic field(e.g., magnetic field emitted in a direction parallel to a plane definedby an upper surface of a respective wafers). After subjecting the wafersto the magnetic field, the residual magnetic fields of the alignmentmarkers were detected at the four correlating depths of the alignmentmarkers (250 nm, 1 μm, 3 μm, and 10 μm) and along both the X-axis andthe Z-axis utilizing one or more of the sensors described above.Furthermore, based on the detected magnetic fields, the correlatingmagnetic field strengths were calculated along both the X-axis and theZ-axis (shown in the associated graphs of FIG. 8 ) via one or more ofthe approximation methods described above.

EXAMPLE 4

FIG. 9 shows testing results 900 from laboratory testing from a fourthexample. Referring to FIGS. 3-5 and 9 together, in the laboratory tests,two types of 1.5 μm×1.5 μm×250 μm alignment markers (specimen shapedlike a rod) were disposed within respective wafers in a directionperpendicular to EXAMPLES 1-3. The first type of alignment markerincluded Fe65Co35, and the second type of alignment marker includedCo20Ni80. Four alignment markers of the first type of alignment markerswere disposed at varying depths (250 nm, 1 μm, 3 μm, and 10 μm) withinfour respective wafers. Additionally, four alignment markers of thesecond type of alignment markers were disposed at varying depths (250nm, 1 μm, 3 μm, and 10 μm) within four respective wafers. All of thewafers were subjected to a magnetic field greater than 25 Oe.Furthermore, the wafers were subjected to an out of plane magnetic field(e.g., magnetic field emitted in a direction perpendicular to a planedefined by an upper surface of a respective wafer). After subjecting thewafers to the magnetic field, the residual magnetic fields of thealignment markers were detected at the four correlating depths of thealignment markers (250 nm, 1 μm, 3 μm, and 10 μm) and along both theX-axis and the Z-axis utilizing one or more of the sensors describedabove. Furthermore, based on the detected magnetic fields, thecorrelating magnetic field strengths were calculated along both theX-axis and the Z-axis (shown in the associated graphs of FIG. 9 ) viaone or more of the approximation methods described above.

Referring again to FIG. 3 , based on data acquired and/or calculated viaone or more of acts 308 a and 308 b (e.g., scalar and/or vectorrepresentations of the magnetic fields of the alignment markers 202along axes of Cartesian space), the alignment system 100 may determinelocations of the alignment markers 202 in three dimensions (e.g., in theX-axis, Y-axis, and Z-axis) within the wafer 114, as shown in act 308 cof FIG. 3 . In other words, in some embodiments, the alignment system100 may determine the locations of the alignment markers 202 as vectorplots.

In the first set of embodiments, as is mentioned briefly above, thegeometries and original orientations and locations of the alignmentmarkers 202 are known, and as a result, the alignment markers 202 haveexpected magnetic field profiles (e.g., three expected vector componentsof the magnetic field profiles). Furthermore, based on the expectedmagnetic fields of the alignment markers 202 and the actualmeasured/calculated magnetic fields of the alignment markers 202, thealignment system 100 may determine the actual locations of the alignmentmarkers 202. For instance, as will be understood by one of ordinaryskill in the art, the alignment system 100 may utilize significantfeatures of known data such as, for example, known locations ofminimums, maximum, zero crossing values, and maximum derivatives of theexpected magnetic fields and original orientations of the alignmentmarkers 202 within the ideal grid relative to significant features ofmeasured and/or calculated data such as, for example, the actualcalculated and/or measured minimums, maximums, zero crossing values, andmaximum derivatives of the detected magnetic fields to determinelocations (e.g., precise locations) of the alignment markers 202 withinthe wafer 114. As a non-limiting example, if an expected response signalis a sinusoidal response (e.g., FIG. 4 ) or other periodic response, thealignment system 100 may utilize the significant features of theexpected response signal and significant features of themeasured/calculated response signal to determine the actual location ofthe alignment markers 202.

Upon determining the locations of the alignment markers 202 within thewafer 114, the method 300 may further include aligning the wafer 114 forfurther semiconductor fabrication processes such as photolithographicprocesses based on the determined locations of the alignment markers 202within the wafer 114, as shown in act 310 of FIG. 3 . For example, thealignment system 100 may align the wafer 114 and/or tools or othercomponents associated with the alignment system 100 based on thedetermined locations of the alignment markers 202. In some embodiments,the alignment system 100 may determine positional offsets (e.g.,displacement data) of the alignment markers 202 relative to the idealgrid, and the processor 120 of alignment system 100 may applymathematical modeling to the displacement data to generate arepresentation of the deviation of the wafer's position relative to theideal grid. For example, the alignment system 100 may fit a simplepartial differential equation to the vector plots of the alignmentmarker locations (e.g., a dx/dy equation) on various orders to determinecoefficients of a standard polynomial equation (e.g., determine ageometrical transformation model). The geometrical transformation modelcan be utilized as a correction set for aligning the wafer 114 forfurther semiconductor fabrication processes.

For example, the alignment system 100 may be used to align the waferand/or tools or other components associated with the alignment system100 via conventional methods. For instance, the alignment system 100 mayalign the wafer and/or associated tools or components via any alignmentalgorithms known in the art. As a non-limiting example, the alignmentsystem 100 may align the wafer and/or associated tools or components bycalculating centers of the alignment markers 202 based on the determinedlocations of the alignment markers 202 and then determining whether thecalculated centers of the alignment markers 202 are within tolerateddimensional ranges relative to the ideal grid (e.g., within a particulardistance from a reference location of the ideal grid). For instance, thealignment system 100 may align the wafer and/or components of thealignment system 100 via any of manners described in U.S. Pat. No.9,748,128, to Chao et al., filed Jun. 1, 2016, U.S. Pat. No. 6,068,954,to David, issued May 20, 2000, and U.S. Pat. No. 8,400,634, to Zhou etal., issued Mar. 19, 2013.

Additionally and after alignment, the method 300 may include exposingthe wafer 114, as shown in act 312 of FIG. 3 . For instance, act 312 mayinclude one or more of spin coating a layer of a radiation-sensitivematerial (commonly referred to as a “photoresist”) onto a surface of thewafer over a film of material, selecting exposing the wafer to radiationthat chemically modifies a portion of the photoresist incident to theradiation, and removing either the exposed portion or the unexposedportion of the photoresist (depending on the positive or negativeformulation of the photoresist) from the surface of the wafer with adeveloper to form a pattern of openings through the photoresistcorresponding to the exposure pattern of the radiation. Subsequently,portions of the material film on the surface of the semiconductor wafermay be selectively removed. Alternatively, portions of a material may bedeposited onto the surface of the wafer, through the openings of thephotoresist mask. Although specific exposure procedures are describedherein, the disclosure is not so limited. Rather, acts 308-310 of FIG. 3may be performed before any further semiconductor fabrication processesthat could benefit from the alignment processes described herein. Ofcourse, acts 308-310 may be repeated between each semiconductor processact to ensure continued alignment of superimposed features of variouslevels.

The method 300 may, optionally, include demagnetizing the alignmentmarkers 202, as shown in act 314 of FIG. 3 . For instance, the alignmentmarkers 202 may be demagnetized by heating the alignment markers 202past the alignment markers' Curie point (i.e., thermal erasure),applying an alternating current (i.e., AC current) through the alignmentmarkers 202, permitting self-demagnetization, etc. Demagnetization ofthe wafer 114 may be desirable so as to not induce artifact intoperformance of integrated circuitry of semiconductor die locationsduring pre-singulation testing. Further, alignment markers 202 arelocated within semiconductor die locations, so as to not induce artifactinto the performance of integrated circuitry components of dicesingulated from the wafer 114, or into circuitry of other componentslocated in close proximity to such semiconductor dice in higher-levelpackaging assemblies.

The method 300 for aligning a wafer described herein may provideadvantages over conventional methods of aligning wafers. For example,because the method 300 utilizes magnetic fields emitted by alignmentmarkers to determine the locations of the alignment markers (i.e.,alignment markers) instead of optical methods, the method 300 is nothindered by opaque materials and/or multiple material levels disposedover the alignment markers, which often hinder conventional opticalscanner alignment systems. Furthermore, the derived alignment positions(e.g., alignment models) are not influenced by a surface topography of awafer, unlike conventional optical alignment systems. Additionally,because detecting the alignment markers is not based on opticaldetection (e.g., limited by image resolutions), the method 300 allowssmaller marker sizes in comparison to conventional alignment systems. Asa result, less wafer real estate may be required for (e.g., wasted on)alignment markers placed outside the die location areas of the wafer,potentially allowing for a greater number of die locations. Moreover,utilizing alignment markers may simplify downstream patchingrequirements and may provide more accurate alignment procedures incomparison to conventional systems. For instance, patching requirementsdo not need to be considered for open or closed status at any oneparticular photo level. In particular, substrates disposed over thealignment markers may remain closed all the times. Additionally,consideration on how to open an area of wafer or whether the wafershould be opened is unnecessary because determining the alignmentmarkers' locations is not impacted by opacity of the substrates disposedover the alignment markers. As a result, the substrates disposed overthe alignment markers may remain un-opened and ma maintain an at leastsubstantially flat topography to alleviate other post processingtopography issues that can cause non-uniformities in critical dimensionpatterns.

Second Set of Embodiments

FIG. 10 shows a schematic flow diagram of a method 1000 of aligning awafer for semiconductor manufacturing processes according to a secondset of embodiments of the present disclosure. As is described in greaterdetail below, the second set of embodiments may include procedures thatinvolve determining locations of alignment markers 202 and an overallorientation of a wafer 114 responsive to measuring and/or detectingmagnetizations (e.g., magnetization forces) of alignment markers 202within the wafer 114 and aligning the wafer 114 responsive to thedetermined locations.

As shown in FIG. 10 , similar to method 300 discussed above in regard toFIG. 3 , the method 1000 includes creating recesses of pattern 204 in asurface (e.g., upper surface) of a wafer 114 (FIGS. 2A and 2B) byremoving material from the wafer 114, as shown in act 1002. In someembodiments, the pattern 204 may be created by conventional lithographicprocesses and methods, as described above. Furthermore, in someembodiments, the created pattern 204 may correlate to (e.g., have thesame size and shape as a pattern) an ideal grid (e.g., ideal patterncomprising ideal positions of the alignment markers 202, and idealorientation of the wafer 114). As is known in the art, positions andlocations of alignment markers within a wafer are conventionallycompared to an ideal grid to determine alignment procedures andmovements (e.g., alignment models). Furthermore, the alignment system100 may form recesses of the pattern 204 such that resulting alignmentmarkers 202 formed within the pattern 204 have particular geometricshapes. Accordingly, selected geometries and locations of the alignmentmarkers 202 may be predetermined and implemented as described above.

The method 1000 may also include filling the pattern 204 withferromagnetic and/or antiferromagnetic materials or any other materialor structure capable of interacting with a magnetic field to form thealignment markers 202, as shown in act 1004 of FIG. 10 . For instance,act 1004 may include filling the pattern 204 with any of the materialsdescribed above in regard to FIGS. 2A and 2B. Furthermore, recesses ofthe pattern 204 may be filled via conventional methods. For example,recesses of the pattern 204 may be filled via electroplating,electroless plating, physical vapor deposition, chemical vapordeposition, ion beam deposition, thin film deposition, etc. The surfaceof wafer 114 may then be subjected to a material removal process suchas, for example, chemical mechanical planarization (CMP) to removematerial from the wafer surface. In some embodiments, the alignmentmarkers 202 may be formed via any of the methods described above inregard to FIG. 3 .

After recesses of the pattern 204 are filled with ferromagnetic and/orantiferromagnetic materials and additional semiconductor fabricationprocesses are continued (e.g., depositing material, patterning, etching,etc.), the alignment system 100 and/or other tools may be employed toalign wafer 114 prior to one or more particular semiconductorfabrication processes. For example, one or more materials (e.g.,overlying material levels) may have already been formed over thealignment markers 202 of the wafer 114. As a result of such materialsover the surface of wafer 114 and alignment markers 202, as well asmovements of the wafer 114, known orientations of the wafer 114 and/ororientations and locations of the alignment markers 202 may be obscuredbut may be easily determined by the alignment system 100. As a result,any previously known positions of wafer 114 and features on the surfacethereof may be redetermined and misalignment in future process actsavoided.

When initiating an alignment procedure, the method 1000 may includeapplying an external magnetic field to the wafer 114, as shown in act1006. For instance, an external magnetic field may have already beenapplied to the wafer 114, or the alignment system 100 may apply anexternal magnetic field to the wafer 114 (e.g., subject the wafer 114 toa magnetic field) via the magnetic source 104 described above in regardto FIG. 1 . For example, the alignment system 100 may supply a currentthrough a coil of wire wrapped around an iron core to create an externalmagnetic field. In some embodiments, the alignment system 100 may supplya sufficient amount of current to create an external magnetic fieldhaving a strength greater than 25 Oe. Moreover, in some embodiments, themagnetic source 104 may be disposed within the sensor 102 of thealignment system 100. For instance, the magnetic source 104 may includean inductor. In one or more embodiments, the alignment system 100 mayapply external magnetic fields to the wafer 114 on microscales ornanoscales. In one or more embodiments, the alignment system 100 may beused to apply the external magnetic field to a pristine, completelyunprocessed (e.g., to form integrated circuitry) wafer 114 immediatelyfollowing filling recesses of the pattern 204 with ferromagnetic and/orantiferromagnetic materials or any other material or structure capableof interacting with a magnetic field and before any further processing.In additional embodiments, alignment system 100 may apply the externalmagnetic field to the wafer 114 after one or more precedingsemiconductor fabrication processes, for example, after opticalalignment markers have become obscured, and prior to or while aligningthe wafer 114 before additional semiconductor manufacturing processes.In some embodiments, applying the external magnetic field to the wafer114 is optional. For instance, the alignment markers 202 may already bemagnetized or may be interacting within magnetic fields.

In some embodiments, the alignment system 100 may apply an externalmagnetic field to the wafer 114 to magnetize the alignment markers 202within the wafer 114. Furthermore, in some embodiments, thephotolithography system 100 may drive a magnetization of the alignmentmarkers 202 within the wafer 114. As noted above, applying an externalmagnetic field to ferromagnetic and/or antiferromagnetic materials maycause the alignment markers 202 to maintain a remanence (e.g., remanentmagnetization or residual magnetism). Accordingly, as is discussed ingreater detail below, in the second set of embodiments, the alignmentsystem 100 may drive a magnetization (e.g., drive an AC magnetic force)of the alignment markers 202 and may measure a response (e.g., physicalforce response) responsive to whether or not magnetized materials (e.g.,the alignment markers 202) are present in the wafer 114.

Upon applying an external magnetic field, the method 1000 may includedetermining (e.g., reading) locations of the alignment markers 202within the wafer 114, as shown in act 1008 of FIG. 10 . In someembodiments, determining the locations of alignment markers 202 withinthe wafer 114 may include measuring magnetizations of the alignmentmarkers 202 within the wafer 114. As used herein the term“magnetization” may refer to a density of magnetic dipole moments thatare induced in a magnetic material when the magnetic material is placednear a magnet (e.g., the alignment markers 202). In one or moreembodiments, act 1006 of FIG. 10 (i.e., the act of applying a magneticfield to the wafer 114) may be repeated during and/or between any of theactions taken in act 1008 to maintain and/or drive magnetization of thealignment markers 202 within the wafer 114.

FIGS. 11 and 12 are schematic representations 1100, 1200 of alignmentmarkers 202 within wafer 114 and a sensor 102 of an alignment system(e.g., alignment system 100) disposed over the wafer 114. Additionally,FIGS. 11 and 12 show example scalar magnitudes of magnetizations of thealignment markers 202 detected via the sensor 102 when passing thesensor 102 over an upper surface 402 of the wafer 114 and above thealignment markers 202 within the wafer 114. As is discussed in greaterdetail below, utilizing data related to the magnetization of thealignment markers 202 to determine locations of the alignment markers202 deems vector data unnecessary within the scope of the second set ofembodiments. Referring to act 1008 and FIGS. 10-12 together, thealignment system 100 may pass the sensor 102 over the upper surface 402of the wafer 114 to detect the magnetizations of the alignment markers202 within the wafer 114. In some embodiments, the alignment system 100may pass the sensor 102 over the wafer 114 along one or more of theX-axis, Y-axis, and/or Z-axis of the Cartesian space defined above inregard to FIG. 1 . For instance, the alignment system 100 may pass thesensor 102 along the X-axis to detect magnitudes of the magnetizationsof the alignment markers 202 along the X-axis of the Cartesian space. Asnoted above, within the second set of embodiments, the sensor 102 mayinclude one or more of a MFM probe, SQUID, or VSM.

As a non-limiting example, in embodiments where the sensor 102 includesan MFM probe, the sensor 102 may include a sharp magnetized tip forscanning the alignment markers within the wafer 114. While passing thesensor 102 over the wafer 114, the alignment system 100 may detectinteractions between the tip and the alignment markers 202 (e.g.,deflections of the tip responsive to a magnetized marker). Furthermore,the alignment system 100 may utilize data from the interactions toreconstruct the magnetic structures of the alignment markers 202 (e.g.,measure magnetization of the alignment markers 202). For example, bothFIGS. 11 and 12 show measured responses (e.g., measured magnitudes ofmagnetization) acquired via the alignment system 100.

As another non-limiting example, in embodiments where the sensor 102includes a VSM, the sensor 102 may include a driver coil and a searchcoil, and the process of measuring the magnetization may includevibrating (as is known in the art) the alignment marker 202 (e.g., thewafer 114). The driver coil (e.g., a first inductor) may be placed on afirst side of an alignment marker 202, and the search coil (e.g., asecond inductor) may be placed on an opposite second side of thealignment marker 202 forming a circuit. The driver coil may generate amagnetic field and may induce magnetization in the alignment marker 202(which may be in addition to any magnetization already present).Additionally, the alignment marker 202 may be vibrated in a sinusoidalor other periodic motion. A magnetic field is emitted by the alignmentmarker 202 due to the magnetization, and the magnetization of thealignment marker 202 may be analyzed as changes occur in relation to thetime of the movement (e.g., vibration) of the alignment marker 202. Forinstance, magnetic flux changes induce a voltage in the search coil thatis proportional to the magnetization of the alignment marker 202. Theinduced voltage may be measured with a lock-in amplifier using apiezoelectric signal as a frequency reference, as is known in the art.Additionally, as is known in the art, changes in the measured signal(e.g., induced voltage) may be converted to values to determine (e.g.,graph) the magnetization of the alignment marker 202 versus the magneticfield strength (known in the art as the Hysteresis loop).

In some embodiments, the alignment system 100 may pass the sensor 102over the upper surface 402 of the wafer 114 along multiple axes (e.g.,both the X-axis and the Y-axis) of the Cartesian space to detect amagnetization of a given alignment marker 202 within the wafer 114 alongthe multiple axes. In one or more embodiments, an expected location agiven alignment marker 202 (e.g., a location determined by the pattern204 previously formed and material previously deposited to form thegiven alignment marker 202, as discussed above in regard to acts 1002and 1004 of FIG. 10 ) may determine where the alignment system 100passes the sensor 102 over the wafer 114 and along which axes thealignment system 100 passes the sensor 102 to detect the magnetizationsof the alignment markers 202.

Referring still to FIG. 10 , based on the data acquired via act 1008(e.g., scalar representations of the magnetizations of the alignmentmarkers 202 along axes of the Cartesian space), the alignment system 100may determine locations of the alignment markers 202 in three dimensions(e.g., in the X-axis, Y-axis, and Z-axis) within the wafer 114. Forinstance, as will be understood by one of ordinary skill in the art, thephotolithography system 100 may utilize significant features of knowndata such as, for example, expected locations of the alignment markers202 within the ideal grid relative to significant features of measureddata such as, for example, the actual measured field vector andmagnetization tensor, minimums, maximums, zero crossing values, 1^(st)and higher order derivatives, and maximum derivatives of the detectedsignals (e.g., magnetizations) to determine locations (e.g., preciselocations) of the alignment markers 202 within the wafer 114. As anon-limiting example, if an expected response signal is a sinusoidalresponse (e.g., FIGS. 11 and 12 ) or other periodic response, thealignment system 100 may utilize the expected response signal andsignificant features of the measured response signal to determine theactual locations of the alignment markers 202.

As is depicted in FIGS. 10-12 , determining locations of the alignmentmarkers 202 by measuring magnetization of the alignment markers 202 mayenable the alignment system 100 to determine locations of the alignmentmarkers 202 that may have magnetic fields that are interacting with eachother. Accordingly, by measuring magnetization of the alignment markers202, the alignment system 100 may allow for alignment markers in closeproximity to each other and having interacting magnetic fields to belocated.

Upon determining the locations of the alignment markers 202 within thewafer 114, the method 1000 may further include aligning the wafer 114for further semiconductor fabrication processes based on the determinedlocations of the alignment markers 202 within the wafer 114, as shown inact 1010 of FIG. 10 . For example, the alignment system 100 may alignthe wafer 114 and/or tools or other components associated with thealignment system 100 based on the determined locations of the alignmentmarkers 202. In some embodiments, the alignment system 100 may determinepositional offsets (e.g., displacement data) of the alignment markers202 relative to the ideal grid, and the processor 120 of alignmentsystem 100 may apply mathematical modeling to the displacement data togenerate a representation of the distortion of the wafer's positionrelative to the ideal grid. For example, the alignment system 100 mayfit a simple partial differential equation to the vector plots ofalignment marker locations (e.g., a dx/dy equation) on various orders todetermine coefficients of a standard polynomial equation (e.g.,determine a geometrical transformation model). The geometricaltransformation model can be utilized as a correction set for aligningthe wafer 114 for further processing (e.g., exposure). For example, thealignment system 100 may align the wafer and/or components of thealignment system 100 via any of the methods described above in regard toFIG. 3 .

Additionally, the method 1000 may include exposing the wafer 114, asshown in act 1012 of FIG. 10 . For instance, act 1012 may includeexposing the wafer 114 via any of the methods described above in regardto FIG. 3 . The method 1000 may, optionally, include demagnetizing thealignment markers, as shown in act 1014 via any of the manners describedabove in regard to FIG. 3 for reasons set forth above.

The method 1000 for aligning a wafer described herein may provide any ofthe advantages described in regard to FIGS. 3-9 . Furthermore, becausemethod 1000 operates by detecting and/or measuring the magnetization ofthe alignment markers 202 instead of the magnetic fields, the method1000 does not depend on orientations of the magnetic moment of thealignment markers 202. For example, method 1000 permits arbitrary, whileoriginally known, shapes and placements of the alignment markers 202within the wafer 114. Accordingly, method 1000 may be advantageous whenshapes and/or orientations of the alignment markers 202 are unknownand/or when orienting domains of the alignment markers 202 is provingdifficult.

Third Set of Embodiments

FIG. 13 shows a schematic flow diagram of a method 1300 of aligning awafer 114 for semiconductor manufacturing processes according to a thirdset of embodiments of the present disclosure. As is described in greaterdetail below, the third set of embodiments may include procedures thatinvolve determining locations of alignment markers and an overallorientation of a wafer 114 responsive to powering the alignment markers,which each include one or more circuits within the wafer 114, with amagnetic field and measuring and/or detecting responses (e.g., signals,feedback, and/or magnetic fields) emanating from the alignment markers(e.g., one or more circuits) within the wafer 114 and aligning the wafer114 responsive to the determined locations.

As shown in FIG. 13 , similar to method 300 discussed above in regard toFIG. 3 , the method 1300 includes creating a recesses in a pattern 204in a surface (e.g., upper surface) of a wafer 114 by removing materialfrom the wafer 114, as shown in act 1302. In some embodiments, thepattern 204 may be created via conventional lithographic processes andmethods, as previously described. Additionally, the pattern 204 maycorrelate to an ideal grid, as discussed above in regard to FIGS. 3 and10 . Accordingly, the alignment system 100 may be used to determinelocations of the alignment markers to be formed within the pattern 204.

As shown in FIG. 13 , the method 1300 may further include disposing orfabricating alignment markers within recesses of the pattern 204, asshown in act 1304 of FIG. 13 . Furthermore, each of the one or morealignment markers may include a circuit that can be powered inductivelyvia a magnetic field. For instance, each of the one or more alignmentmarkers may include any conventional receiving inductor for powering thecircuit. Additionally, each of the one or more alignment markers mayinclude microcircuitry or nanocircuitry or an inductively powerable MEMSdevice operably coupled to inductively-driven power circuitry.

In one or more embodiments, each alignment markers may include anantenna. For example, the alignment markers may include any conventionalmicro-antennae or nano-antennae. In additional embodiments, the one ormore alignment markers may include components for producing AC magneticfields. For instance, the one or more alignment markers may include oneor more solenoids or coils for producing AC magnetic fields.Additionally, each alignment marker may be capable of emittingelectromagnetic fields, DC magnetic fields, acoustic vibrations, thermalemissions, photon emissions, and/or other responses (vector or scalar).In some embodiments, the alignment marker 202 may include an array ofantennae that may utilize beam shaping and/or other methods to control adirectionality of radiation from the array of antennae. Additionally,the alignment marker 202 may drive a ferromagnetic core of flux channelthat emits an AC magnetic field.

The method 1300 may further include applying an external magnetic fieldto the wafer 114, as shown in act 1306 of FIG. 13 . In some embodiments,the alignment system 100 may apply the external magnetic field via themagnetic source 104. In one or more embodiments, the alignment system100 may apply the external magnetic field to an entirety of the wafer114. In additional embodiments, the alignment system 100 may apply theexternal magnetic field to only regions of the wafer 114. In furtherembodiments, the alignment system 100 may apply the external magneticfield to only an expected location of an alignment marker (e.g., acircuit). For instance, in some embodiments, the magnetic source 104 maybe disposed within the sensor 102 or carried by the structure to whichsensor 102 is mounted. As a non-limiting example, the magnetic source104 may include a voltage source and an inductor. The voltage source mayby coupled to the inductor (via traces, wires, etc.) to cause a voltageacross the inductor, and as a result, cause the inductor to emit anexternal magnetic field around the inductor.

In response to applying an external magnetic field to the wafer 114,method 1300 may include powering the one or more of the alignmentmarkers (e.g., one or more circuits) within the wafer 114, as shown inact 1308 of FIG. 13 . For instance, the inductors of the one or morealignment markers may create voltages across the inductors in responseto the applied external magnetic field, and the voltages may power thecircuits of the one or more alignment markers. Powering the one or morealignment markers may result in signals being emitted by antennae of theone or more alignment markers, AC magnetic fields being emitted by coilsof the one or more alignment markers, electromagnetic fields to beemitted by a coil of the one or more alignment markers, acousticvibrations to be emitted by the one or more alignment markers, thermalemissions to be emitted by the one or more alignment markers, or otherresponses (vector or scalar) to be emitted by the one or more alignmentmarkers.

Additionally, the method 1300 may include detecting and/or measuring theresponses from the one or more alignment markers, as shown in act 1310of FIG. 13 . For instance, in some embodiments, detecting and/ormeasuring the responses from the one or more alignment markers mayinclude detecting magnetic fields emitted by the one or more alignmentmarkers via any of the manners described above in regard to FIGS. 1-12 .In additional embodiments, detecting and/or measuring the responses fromthe one or more alignment markers may include receiving signals (e.g.,radiofrequency signals, electromagnetic emissions, etc.) from antennaeof the one or more alignment markers. In further embodiments, whereinalignment markers are configured as MEMS devices, vibrations may beinitiated responsive to inductive power, and such vibrations, themagnitude, frequency and waveform thereof, may be detected and measuredby sensor 102.

Furthermore, responsive to the detected and/or measured responses fromthe from the one or more alignment markers, the method 1300 may includedetermining locations of the one or more alignment markers within thewafer 114, as shown in act 1312 of FIG. 13 . In some embodiments,determining locations of the one or more alignment markers within thewafer 114 may include determining a location of the sensor 102 over thewafer 114 relative to a remainder of the wafer 114. For instance, inoperation and use, the magnetic source 104 may power a circuit withinthe wafer 114, and based on the response from the circuit, the alignmentsystem 100 can determine where the sensor 102, magnetic source 104,and/or other tool of the alignment system 100 is located over the wafer114. Additionally, in one or more embodiments, the alignment system 100may determine the locations of the one or more alignment markers via anyof the methods described above in regard to FIGS. 1-12 .

Moreover, the method 1300 may include powering off the circuits viaconventional methods, as shown in act 1314 of FIG. 13 . Additionally,the method 1300 may include aligning the wafer 114 and/or the alignmentsystem 100 as shown in act 1316 of FIG. 13 via any of the methodsdescribed above in regard to FIGS. 3 and 10 . Likewise, the method 1300may include exposing the wafer 114, as shown in act 1318 of FIG. 13 viaany of the methods described above in regard to FIGS. 3 and 10 .

FIG. 14 is a schematic representation of a sensor head 1401 that may beutilized with the methods described in regard to FIG. 13 . In someembodiments, as described above, the wafer 114 may include an array ofalignment markers 202 within the wafer 114. Furthermore, the sensor head1401 may include a complimentary set of markers 1403. For instance, thesensor head 1401 may include an inductive bridge circuit that mayamplify small differences in coupling between two inductor pairs (e.g.,correlating markers between the array of alignment markers 202 and theset of markers 1403 of the sensor head 1401). Additionally, the sensorhead 1401 may be utilized via any of the manners described above inregard to FIG. 13 .

Referring to FIGS. 1-14 together, additional embodiments of the presentdisclosure may include metal detector technologies for locatingnon-magnetized alignment markers, placing the alignment markers withindie, and unique alignment marker designs with fewer design constraintsthan conventional, only visually detectable alignment markers.

An embodiment of the present disclosure includes a wafer comprising asemiconductor material, and one or more alignment markers comprising atleast one of a ferromagnetic material or an antiferromagnetic materialor any other material or structure capable of interacting with amagnetic field.

One or more embodiments of the present disclosure include a method ofaligning a wafer. The method may include applying a magnetic field to awafer, detecting residual magnetic fields from one or more alignmentmarkers within the wafer, responsive to the detected residual magneticfields, determining locations of the one or more alignment markers,determining a geometrical transformation model for aligning the wafer,and aligning the wafer responsive to the geometrical transformationmodel.

Some embodiments of the present disclosure include a method of aligninga wafer. The method may include driving magnetization of at least onealignment marker within a wafer, measuring the magnetization of the atleast alignment marker, responsive to the magnetization of the at leastone alignment marker, determining a location of the at least onealignment markers relative to an ideal grid, determining a geometricaltransformation model for aligning the wafer, and aligning the waferresponsive to the geometrical transformation model.

One or more embodiments of the present disclosure include a method ofaligning a wafer. The method may include applying a magnetic field to awafer having one or more alignment markers comprising a ferromagnetic orantiferromagnetic material or any other material or structure capable ofinteracting with a magnetic field, detecting one or more magneticattributes of the one or more alignment markers with a sensor, andresponsive to the one or more magnetic attributes, determining locationsof the one or more alignment markers.

Some embodiments of the present disclosure include an alignment system.The alignment system may include a substrate support for supporting awafer, a sensor movable over the wafer and configured to detect magneticattributes of alignment markers within the wafer, and a controller. Thecontroller may be operably coupled to the substrate support, themagnetic source, and the sensor. The controller may include at least oneprocessor and at least one non-transitory computer-readable storagemedium storing instructions thereon that, when executed by the at leastone processor, cause the controller to receive data related to detectedmagnetic attributes of the alignment markers from the sensor, andresponsive to the received data, determine locations of the alignmentmarkers within the wafer.

The embodiments of the disclosure described above and illustrated in theaccompanying drawings do not limit the scope of the disclosure, which isencompassed by the scope of the appended claims and their legalequivalents. Any equivalent embodiments are within the scope of thisdisclosure. Indeed, various modifications of the disclosure, in additionto those shown and described herein, such as alternate usefulcombinations of the elements described, will become apparent to thoseskilled in the art from the description. Such modifications andembodiments also fall within the scope of the appended claims andequivalents.

What is claimed is:
 1. An alignment system, comprising: a substrate support for supporting a wafer; a sensor movable over the wafer and configured to detect magnetic attributes of alignment markers within the wafer; and a controller operably coupled to the substrate support and sensor, the controller comprising: at least one processor; and at least one non-transitory computer-readable storage medium storing instructions thereon that, when executed by the at least one processor, cause the controller to: receive data related to detected magnetic attributes of the alignment markers from the sensor; and responsive to the received data, determine locations of the alignment markers within the wafer.
 2. The alignment system of claim 1, wherein the controller further comprises instructions that, when executed by the at least one processor, cause the controller to determine locations of the alignment markers within the wafer relative to an ideal grid.
 3. The alignment system of claim 2, wherein the controller further comprises instructions that, when executed by the at least one processor, cause the controller to calculate a geometrical transformation model for aligning the wafer relative to the ideal grid.
 4. The alignment system of claim 3, wherein the controller further comprises instructions that, when executed by the at least one processor, cause the controller to align the wafer using the substrate support based at least partially on the geometrical transformation model.
 5. The alignment system of claim 3, wherein the controller further comprises instructions that, when executed by the at least one processor, cause the controller to align the wafer using the substrate support responsive to the determined locations of the alignment markers.
 6. The alignment system of claim 1, wherein the sensor is selected from the group consisting of a MFM probe, a SQUID, or VSM.
 7. The alignment system of claim 1, wherein the sensor is selected from the group consisting of a Hall Effect sensor, a GMR sensor, a TMR sensor, an EMR sensor, or a spin hall sensor.
 8. The alignment system of claim 1, further comprising a magnetic source located and configured to apply a magnetic field to at least a portion of a wafer carried on the substrate support.
 9. The alignment system of claim 8, wherein the magnetic source comprises an electro magnet.
 10. The alignment system of claim 1, wherein the sensor is configured to detect residual magnetic fields emitted by the alignment markers.
 11. The alignment system of claim 1, wherein the sensor is configured to detect magnetizations of the alignment markers.
 12. A wafer comprising: a substrate comprising a semiconductor material; and one or more alignment markers comprising at least one of a ferromagnetic material or an antiferromagnetic material or any other material or structure detectable responsive to exposure to a proximate magnetic field.
 13. The wafer of claim 12, wherein the one or more alignment markers comprise a pattern of recesses formed in a surface of the wafer, the pattern of recesses being at least partially filled with at least one of the ferromagnetic material, the antiferromagnetic material, or any other material or structure detectable responsive to exposure to a proximate magnetic field.
 14. The wafer of claim 12, wherein the one or more alignment markers have longitudinal ends aligned along one of an X-axis, a Y-axis, or a Z-axis of a Cartesian space.
 15. A wafer comprising: a substrate comprising a semiconductor material; and one or more alignment markers comprising one or more inductively powerable circuits within recesses of a pattern within the substrate.
 16. An alignment system, comprising: a substrate support for supporting a wafer; a sensor movable over the wafer and configured to detect responses of alignment markers within the wafer; a magnetic source located and configured to apply a magnetic field to at least a portion of the wafer or drive a magnetization of the alignment markers within the wafer; and a controller operably coupled to the substrate support and sensor, the controller comprising: at least one processor; and at least one non-transitory computer-readable storage medium storing instructions thereon that, when executed by the at least one processor, cause the controller to: receive data related to detected responses of the alignment markers from the sensor; and responsive to the received data, determine locations of the alignment markers within the wafer.
 17. The alignment system of claim 16, wherein the controller further comprises instructions that, when executed by the at least one processor, cause the controller to determine locations of the alignment markers within the wafer relative to an ideal grid based at least partially on the responses of the alignment markers.
 18. The alignment system of claim 17, wherein the controller further comprises instructions that, when executed by the at least one processor, cause the controller to calculate a geometrical transformation model for aligning the wafer relative to the ideal grid.
 19. The alignment system of claim 18, wherein the controller further comprises instructions that, when executed by the at least one processor, cause the controller to cause the alignment system to align the wafer responsive to the geometrical transformation model.
 20. The alignment system of claim 16, wherein the responses of the alignment markers comprise one or more of residual magnetic fields, magnetization, or photon emissions. 